AMBULANCE attendances associated with the misuse of pregabalin — an anticonvulsant often prescribed as a sedative — have increased tenfold in Victoria since 2012, mirroring an increase in prescription rates, according to the authors of research published online today by the Medical Journal of Australia.

Originally developed as an anti-epileptic agent, pregabalin is now also used to treat fibromyalgia, generalised anxiety disorder, and neuropathic pain. It is subsidised by the Pharmaceutical Benefits Scheme as an anti-epileptic and, since 2013, for treating neuropathic pain. Since 2015, total PBS costs for pregabalin are among the highest for any drug.

According to Rose Crossin, lead author and a research officer at the Turning Point Alcohol and Drug Centre in Melbourne, and colleagues, pregabalin misuse has been on the rise around the world.

“Individuals take higher than recommended doses of pregabalin for its euphoric effects … or is implicated in self-harm,” Crossin and colleagues wrote. “There is a growing black market for pregabalin in populations at high risk of misuse, including in prisons, where pregabalin is sometimes prescribed for pain relief in preference to opioids. Alcohol should not be consumed while taking pregabalin, and additive side effects are also possible if it is taken with other central nervous system depressants, including benzodiazepines and narcotic pain medications.”

Crossin and colleagues undertook a retrospective analysis of data on ambulance attendances in Victoria between January 2012 and December 2017 for which pregabalin misuse-related misuse was a contributing factor.

“There were 1201 pregabalin misuse-related attendances during the study period; the rate increased from 0.28 cases per 100 000 population in the first half of 2012 to 3.32 cases per 100 000 in the second half of 2017. The [ambulance] attendance rate was strongly correlated with prescription rates in Australia. [Of those attendances] 593 (49%) were for people with a history that may have contraindicated prescribing pregabalin. Pregabalin was frequently misused with other sedatives (812 attendances, 68%), particularly benzodiazepines (440, 37%); 472 attendances (39%) were associated with a suicide attempt.

“People who misused pregabalin with other sedatives more frequently presented with moderate to severe impairments of consciousness, but the frequency of suicide attempts was similar whether other sedatives were concurrently used or not.”

The authors warned that physicians needed to be particularly cautious when prescribing pregabalin.

“Clinicians should ensure that consumers are aware of the risks of these interactions, and be particularly cautious when considering prescribing pregabalin for patients who are taking other sedatives,” they wrote.

“Interventions being considered in other countries may be relevant to Australia, including changes to scheduling, as implemented or planned in the United Kingdom, the United States, and Norway, and limits on dispensing to minimise the risks of pregabalin misuse.”

Cate Swannell

Correspondence:

Publication of your online response is subject to the Medical Journal of Australia's editorial discretion. You will be notified by email within five working days should your response be accepted.